Groove cutting fastener

ABSTRACT

A sheet metal nut element for cutting a groove or thread channel on a smooth shank is formed with a plurality of teeth on the peripheral edge of an aperture which receives a shank. The periphery of the aperture is interrupted by breaks or discontinuities and each tooth is formed by an angle at the intersection of the peripheral edge and the edge of a discontinuity. The edge between the discontinuities is deflected axially to lie in a spiral curve and extend radially inwardly of the spiral curve and form teeth that cut a groove in the shank.

United States Patent 22 Filed George A. Tinnerman 17864 Beach Road,Lakewood, Ohio 44104 [211 App]. No. 816,956

Apr. 17, 1969 Division ofSer. No. 569,478, Aug. 1, 1966, P?! N9? [45]Patented Mar. 16,1971

[ 72] Inventor [54] GROOVE CUTTING FASTENER 2 Claims, 7 Drawing Figs.

[52] U.S. Cl 85/32 F16b 37/02 Field of Search 85/36, 32

(Int.); 10/152 [56] References Cited UNITED STATES PATENTS 2,969,705l/l96l Becker 85/36 2,986,059 5/1961 Duffy et al. 85/32 lnt. 2,561,0367/1951 Sodders.... 85/36 3,345,899 l0/l967 Fiddler 85/32 Int.

Primary Examiner- Edward C. Allen Att0rneys-Revere B. Gurley and ArthurH. VanHorn ABSTRACT: A sheet metal nut element for cutting a groove orthread channel on a smooth shank is formed with a plurality of teeth onthe peripheral edge of an aperture which receives a shank. The peripheryof the aperture is interrupted by breaks or discontinuities and eachtooth is formed by an angle at the intersection of the peripheral edgeand the edge of a discontinuity. The edge between the discontinuities isdeflected axially to lie in a spiral curve and extend radially inwardlyof the spiral curve and form teeth that cut a groove in the shank.

- Patented March 16, 1971 3,570,36l

" &//////////////////// FIG. 7

INVENTOR. GEORGE A. TINNERMAN BY I GRGGVE CUTTING FASTENER Thisapplication is a division of Ser. No. 569,478, filed Aug. 1, 1966, forGroove Cutting Rotating Fastener. now Pat. No. 3,456,705, issued Jul.22, I966.

My invention relates to a fastener in which one of two relativelyrotatable members extends through an aperture in the other, and the twomembers are secured together by teeth on the apertured member which cutthreads in the surface of the other member. The apertured member may bea nut or equivalent and the member projecting through the aperture isusually in the form of a stud or shank.

Some types of fasteners are already known in which the nut or similarelement forms its own thread on an unthreaded rod or stud, but thesehave disadvantages because of size, either radially or axially of thestud. It is also difficult in many of these fasteners to align the nutproperly on the stud due to rocking of the nut about its points ofengagement, so that extreme care is required of the operator to maintainalignment.

It is therefore one of the objects of this invention to construct afastener which preferably is made of suitable sheet material and whichis provided with means for cutting a groove or thread channel in anunthreaded stud or the like during relative rotative movement betweenthe fastener and the stud.

Another object is a fastener of the type disclosed herein which isprovided with a plurality of substantially radially disposed multiplecutting means arranged at three or more points in an opposed fashionabout a stud or shank-receiving opening in the fastener for threadchannel-cutting engagement therewith.

A further object is a multitoothedthread-cutting fastener formed of arelatively stiff sheet material which is self-aligning with respect tothe axis of the stud or shank on which it is applied.

Another object of the invention is a structure which is adapted to theeconomical use of prehardened and prefinished materials, therebyeliminating costly hardening and tempering operations.

Still another object is a relatively thin-walled fastener of stiff sheetmaterial having a stud-receiving opening therein and provided with atleast three stud-engaging thread-cutting means arranged along a helicalpath about the opening.

Still another object is to provide a multitoothed threadcutting fastenerby which a continuous single groove or thread channel may be formedalong the stud permitting the associated parts to be drawn tightlytogether in clamped assembled position.

Another object of my invention is the formation of a fastener withaxially spaced thread channel-cutting elements, each terminating in apoint to form'a cutting tooth, the points if projected on a planedefining a circle, its center lying in the axis of rotation of thefastener when rotated on a shank.

Other and further objects and advantages of this invention will becomemore apparent from the following description and claims, reference beingmade to the accompanying drawing which shows several embodiments of thepresent invention and the principles thereof, and in which drawing likereference characters are employed to designate like parts throughout thesame.

In the drawings:

FIG. I is a perspective view of a fastener embodying one form of myinvention;

FIG. 2 is a modified form;

, FIG. 3 is a view looking in the direction of the arrows 3-3 of FIG. 2and illustrates one of the locating and positioning edges and itsassociated groove or thread channel cutting tooth;

FIG. t illustrates still another modified form of fastener embodying myinvention;

FIG. 5 is a view partly in section as taken on line 5-5 of FIG. 45,showing the fastener driven home on the stud by means of a wrench orother tool as a result of forming its own thread channel in the studduring such operation;

FIG. 6 is a perspective view of a further modification of the inventionwherein the fastener is enclosed within a molded body of suitableplastic material, the body being formed with tool engaging faces; and

FIG. 7 is a vertical section taken on line 7-7 of FIG. 6.

A fastener which illustrates specifically my invention as applied to anutlike element which may be secured to a shank or stud is shown inFIGS. 1 to 5, in which the thread channel or groove forming structureare the same. The fastener 1 in FIG. 1 has an aperture 2 to receive astud 3 as shown in FIG. 5. The periphery of this aperture 2 isinterrupted or is discontinuous at three spaced points 4, the slots ornotches 5 extending outwardly from the periphery bordered by the sideedges 6, 7.

As shown in FIG. 2, the side edges 7 are shorter than the side edges 6,so that the inner ends of side edges 6 are closer to the axis of theaperture and lie substantially in a circle 8 of smaller radius than theinner ends of edges 7, which lie on the circle 9. The edge 10 of theaperture 2 connecting the inner end of one side edge 7 with the innerend of the side edge 6 of the adjacent notch 4 decreases in distancefrom the center, as will be seen in FIG. 2, this spiral edge terminatingin a tooth 11a. This tooth is formed by the extension of the spiral edgecurving inwardly of a continuation of the spiral curve of said spiraledge and intersecting the side edge 6 at an acute angle to form theinwardly directed tooth as shown at 11a in FIGS. 1 and 2. As is bestshown in FIG. 3, this edge 10 of the aperture is deflected out of theplane of the circle 9, as at 12a, to lie in a spiral path, the tooth 11aextending inwardly of the periphery, the edge 10 sloping from the planeof the circle 9 to the inwardly directed tooth 11a.

Shown in these FIGS. are three notches or discontinuities 4 in theperiphery of opening 2, and three arcuate edges 10 between thesediscontinuities. The three teeth Ila, llb, 11c are not in the sameplane, but are at the end of unequally deflected portions 12a, 12b, 12c.The teeth lie in a spiral curve, and each tooth is spaced axially fromits adjacent tooth by one-third of the pitch distance of the helicalgroove to be formed in the stud when the element 1 is rotated on a stud.The sides of the inwardly directed teeth adjacent the edges 12a, 12b,form the cutting edges of the teeth and the edges 12a, 12b, 12c engagethe stud 13 at an acute angle and with the three cutting teeth 11a, 11b,11c maintain the nut element on the stud in axial alignment. The threeteeth engage the stud 3 with equal pressure, since the fastener I isfree to move laterally until the forces acting on the three teeth areequal. Under equal pressure, the teeth will cut the shank equally. Theedges may be so inclined that the groove being cut by one tooth isengaged by the edge of the following tooth, so that the next tooth cutsdeeper in the same groove, and the edges guide the teeth in cutting asingle helical groove or thread channel 14, as shown in FIG. 5.

Each tooth contributes to cutting the groove, and this groove or threadchannel 14 will be deeper by the removal of on the order of three timesas much material as one tooth would remove. As aresult, the fastener Iengages the stud 13 in a groove 14 substantially deeper than if theteeth formed separate grooves.

This fastener may be made from hardened steel, and the hardened cuttingteeth are thus provided without necessity for subsequent hardeningoperation.

The forms of fastener shown in FIGS. I to 5 differ by the formations formanufacture and wrench engagement. In FIG. I, the strip 20 may bepunched and formed by successive actions. The strip may then be cut andbent as shown by dotted lines 21 to provide wrench seats 22.

The element in FIG. 2 is provided with tool engaging arms 23, while inFIGS. 4 and 5, flanges 24 provide for engagement of wrench 25. The stud3 may be tapered as shown, and the single groove I4 is cut by the joint,successive action of the three cutting teeth.

The fastener or nut element having cutting teeth to cut a deep, singlegroove in a stud or shank may be incorporated in a rigid or semirigidplastic body to form a composite fastener.

in FIGS. 6 and 7, the metal fastener element 31 has cutting teeth whichare the same as those in FIGS. 1 to and engage a stud 26 to cut a groove27 in the stud. This metal fastener element is incorporated in a body 32of plastic material of rigid or semirigid type, which may be consideredessentially rigid. This plastic body is similar to the nut body of thecomposite nut disclosed and claimed in the Tinnerman application, Ser.No. 549,880, filed May 13, 1966 now U.S. Pat. No. 3,468,212. In the formillustrated here, the metal fastener element 31 extends to the peripheryon opposite sides of the plastic body, and is spaced from the oppositeend faces-33, 33a of the body. The plastic body 32 has a polygonal 34portion to operate as a wrench seat for rotating the composite fasteneron the stud, and the lower or engaging face 32 of the plastic body ishollowed at 35, so that only a peripheral portion 36 engages initiallythe surface of a member 37 engaged by the fastener. As the fastener istightened, the cutting teeth of the metal fastener element 31 willengage the groove 27 cut in the stud 3 to exert pressure on the plasticbody, compacting the body against the stud and the member engaged, anddistorting the hollow base, providing a resilient and liquid-tightengagement. At the same time, the essentially rigid plastic body 32 willreduce distortion of the metal element 31, with resilient resistance todeflection of the metal components.

The specific examples of my invention described herein are intended toillustrate the invention which contemplates various modifications withinthe spirit and scope of the appended claims.

lclaim:

l. A sheet metal, apertured, groove-cutting fastener element havinggroove-cutting teeth in the aperture which cut a spiral groove formationin a shank upon relative rotation on a shank in said aperture, theperiphery of said aperture comprising at least three segments betweendiscontinuities in said periphery, each discontinuity having a side edgeextending outwardly from the periphery, each segment having an edgelaying in a spiral curve extending from one discontinuity to a tooth atthe side edge of the following discontinuity, each said tooth beingformed by the intersection at an acute angle of an edge extendinginwardly of a continuation of the spiral curve of a spiral edge of asegment with said side edge of a discontinuity to form a sharply pointedtooth directed inwardly of said periphery, said spiral edges beingaxially deflected out of the plane of the body of said fastener element,so that the fastener element will thread upon a shank as each tooth cutsa spiral groove formation in said shank.

2. A sheet metal, apertured, groove-cutting fastener element forthreading on to a smooth surface shank by cutting a spiral grooveformation in said shank upon relative rotation, comprising a sheet metalfastener element having an aperture therethrough, the periphery of saidaperture being interrupted by at least three discontinuities, eachdiscontinuity being formed with an edge extending outwardly from saidperiphery, said periphery being axially deflected out of the plane ofsaid sheet metal between each two discontinuities to form a spiral edgeextending from one discontinuity to a tooth at the outwardly extendingedge of the following discontinuity, each said tooth being formed by theintersection at an acute angle of an edge extending inwardly of acontinuation of the spiral curve of said spiral edge with said outwardlyextending edge of said discontinuity to form a sharp groove-cuttingtooth extending inwardly of said periphery with its leading edgeengaging the surface of said shank at an acute angle at the point ofcontact when rotated on said stud and its trailing edge the outwardlydirected edge of said discontinuity, successive cutting teeth beingspaced axially on a spiral curve an axial distance of one-third of thepitch distance of a single spiral groove cut in said shank.

1. A sheet metal, apertured, groove-cutting fastener element havinggroove-cutting teeth in the aperture which cut a spiral groove formationin a shank upon relative rotation on a shank in said aperture, theperiphery of said aperture comprising at least three segments betweendiscontinuities in said periphery, each discontinuity having a side edgeextending outwardly from the periphery, each segment having an edgelaying in a spiral curve extending from one discontinuity to a tooth atthe side edge of the following discontinuity, each said tooth beingformed by the intersection at an acute angle of an edge extendinginwardly of a continuation of the spiral curve of a spiral edge of asegment with said side edge of a discontinuity to form a sharply pointedtooth directed inwardly of said periphery, said spiral edges beingaxially deflected out of the plane of the body of said fastener element,So that the fastener element will thread upon a shank as each tooth cutsa spiral groove formation in said shank.
 2. A sheet metal, apertured,groove-cutting fastener element for threading on to a smooth surfaceshank by cutting a spiral groove formation in said shank upon relativerotation, comprising a sheet metal fastener element having an aperturetherethrough, the periphery of said aperture being interrupted by atleast three discontinuities, each discontinuity being formed with anedge extending outwardly from said periphery, said periphery beingaxially deflected out of the plane of said sheet metal between each twodiscontinuities to form a spiral edge extending from one discontinuityto a tooth at the outwardly extending edge of the followingdiscontinuity, each said tooth being formed by the intersection at anacute angle of an edge extending inwardly of a continuation of thespiral curve of said spiral edge with said outwardly extending edge ofsaid discontinuity to form a sharp groove-cutting tooth extendinginwardly of said periphery with its leading edge engaging the surface ofsaid shank at an acute angle at the point of contact when rotated onsaid stud and its trailing edge the outwardly directed edge of saiddiscontinuity, successive cutting teeth being spaced axially on a spiralcurve an axial distance of one-third of the pitch distance of a singlespiral groove cut in said shank.